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First record of squamate reptiles from the Oligocene of South America
Abstract
Squamata are known from South America since the Cretaceous, but their fossil record has an occurrence gap between the late Eocene and early Miocene. Fossils recovered from the Sarmiento Formation (Deseadan South American Land Mammal Age, late Oligocene) at Cabeza Blanca (45°S) partially fill this interval. The squamates recovered from Cabeza Blanca include both lizards (an indeterminate Iguanidae and a probable Iguaninae) and snakes (Madtsoiidae). If these taxonomic assignments are correct, the presence of an Iguaninae at such a latitude is unexpected because these lizards are presently absent from Argentine territory. The madtsoiid, here referred to Madtsoia, would extend the Cenozoic record of this genus back
to around 16 Ma. The squamate fauna from Cabeza Blanca is compatible with warm and humid environments inferred for the Patagonian Deseadan.
... The fact that vertebrae are the most polyvalent part of the skeleton (Hoffstetter & Gasc, 1969) and the scarce knowledge of extant lizard vertebrae morphological diversity is a major problem for precise taxonomic assignation of these elements. Albino & Brizuela (2014b) present a basic evaluation of the vertebral anatomy of some members of extant Argentine lizards families. In that framework, this fossil vertebra can be excluded from Anguidae and Scincidae, since these taxa lack zygosphenal articulation facets (i.e., there are no articulation medial to those of the prezygapophyses). ...
... In that framework, this fossil vertebra can be excluded from Anguidae and Scincidae, since these taxa lack zygosphenal articulation facets (i.e., there are no articulation medial to those of the prezygapophyses). Furthermore, the absence of a distinct tenon for the zygosphenal articulation excludes the specimen from Teiidae, as well as some Pleurodonta (Hoffstetter & Gasc, 1969;Albino & Brizuela, 2014b). Unlike Gymnophthalmidae, the zygosphenal articulation facets are dorsolateral and lack the crest limiting the zygosphenal articulation facets (Albino & Brizuela, 2014b). ...
... Furthermore, the absence of a distinct tenon for the zygosphenal articulation excludes the specimen from Teiidae, as well as some Pleurodonta (Hoffstetter & Gasc, 1969;Albino & Brizuela, 2014b). Unlike Gymnophthalmidae, the zygosphenal articulation facets are dorsolateral and lack the crest limiting the zygosphenal articulation facets (Albino & Brizuela, 2014b). Also, MMSCM 2021 presents poorly developed and dorsolateral orientated zygosphenal articulation facets. ...
Fossils of amphibians and squamates are relatively common in Pliocene–Pleistocene sediments in the southeastern Atlantic coast of Buenos Aires Province (Argentina), particularly in the southern slope of the Tandilia mountain system. These taxa are less known in the northern slope, which in the county of Mar Chiquita are solely represented by one anuran record. Here, new herpetofaunal material is described from Mar Chiquita county in the northern slope of the Tandilia mountain system. These specimens, while few, present an interesting taxonomical and morphological diversity. From the Ensenadan outcrops, amphibians are represented by cf. Rhinella. On the other hand, Stenocercus, an indeterminate tropidurid, Colubroides, and an indeterminate snake account for the Ensenadan squamates. In the Bonaerian outcrops, squamates are represented by the viperid Bothrops and an indeterminate Pleurodont. These latter taxa are also present in the Lujanian with an indeterminatesnake. These are the first fossil records of squamates from Mar Chiquita and together with the new and previous amphibian records constitute a herpetological assemblage (Ceratophrys ornata, cf. Rhinella, Stenocercus, and Bothrops) that suggests that the paleoclimatic conditions during the Pleistocene of the Pampean region would have been similar to those of the present day. This inference should be considered with caution, since it contradicts those suggested by the mammalian record, which is richer and presents taxonomic identifications that are more precise. Mammalian fossil records indicate a cold and dry glacial Pleistocene interspersed with short, warmer, and more humid periods.
... At least 24 species in 15 genera have been described as belonging to this clade, with a widespread but mainly Gondwanan distribution (LaDuke et al., 2010;Rage et al., 2014;Rio and Mannion, 2017;Gómez et al., 2019). They are recorded after the Eocene only in Australia, Argentina, and India (Scanlon, 2004;Albino and Brizuela, 2014;Wasim et al., 2022). ...
... Rionegrophis madtsoioides (Albino, 1986(Albino, , 2007, with an estimated length between 2 and 4 meters, represents a mid-sized form, and Eomadtsoia ragei, with an estimated length surpassing 4 meters is considered a large-sized form (Gómez et al., 2019). In contrast, South American Cenozoic records are less diverse and only represented by the mid-to-large form Madtsoia (Simpson, 1933;Albino, 1993;Albino and Brizuela, 2014;Rage, 1998). ...
... Madtsoiids are tentatively known from Paleocene deposits in South America from a possible specimen from Bolivia (Rage, 1991), but are well represented from Eocene deposits, with two species being currently described: Madtsoia bai Simpson, 1933 from Patagonia, Argentina and Madtsoia camposi Rage, 1998 from Brazil. A vertebral centrum tentatively referred to the genus Madtsoia from the Oligocene of Patagonia represents the youngest record of madtsoiids outside Australia and India (Albino and Brizuela, 2014;Wasim et al., 2022). ...
The Madtsoiidae are an extinct lineage of snakes known from the Late Cretaceous to the Late Pleistocene, with a rich fossil record distributed mainly across Gondwanan landmasses. However, only a few taxa are represented by cranial or articulated remains, and most madtsoiids are known only by isolated vertebrae. The unambiguous record of Madtsoiidae from the Cenozoic in South America had been restricted to the genus Madtsoia from Eocene and Oligocene deposits of Patagonia and Brazil. Here, we describe a new madtsoiid taxon, Powellophis andina gen. et sp. nov., based on an articulated postcranial skeleton from the Mealla Formation (middle–late Paleocene) in northwestern Argentina. The new taxon is estimated to be around 3 meters long, with a vertebral morphology sharing similar features with other mid-to-large forms. Its inclusion in a recent analysis of madtsoiid relationships recovers Powellophis as an early member of a clade formed by mostly large bodied and gigantic taxa. Its presence in the Paleocene of northwestern Argentina fills the gap between the diverse Late Cretaceous and Eocene–Oligocene records of madtsoiids in South America, confirms their presence in northern Gondwana by the early Paleogene, and expands the diversity of the group.
... Recently, fossils found in levels attributed to the Late Oligocene of the Sarmiento Formation (Deseadan SALMA) at the locality of Cabeza Blanca, in Chubut Province [Fig. 6.3 (3)], partially fill this interval (Albino and Brizuela 2014b). The squamates recovered in this Patagonian site include two remains which belong to lizards: a tooth-bearing fragment appertaining to a maxilla or dentary (MPEF PV 1460) and an isolated presacral vertebra (MPEF PV 1463). ...
... The squamates recovered in this Patagonian site include two remains which belong to lizards: a tooth-bearing fragment appertaining to a maxilla or dentary (MPEF PV 1460) and an isolated presacral vertebra (MPEF PV 1463). The first was assigned to an indeterminate Iguanidae, whereas the latter probably belongs to an Iguaninae (Albino and Brizuela 2014b). Until the moment, no other Palaeogene iguanian was reported for South America. ...
... For the Late Palaeogene, the presence of an Iguaninae at a latitude of 45° S in the late Oligocene of Patagonia (Albino and Brizuela 2014b) is unexpected because these lizards are presently absent from the Argentine territory. Extant Iguaninae are mainly distributed from United States through Central America and the Caribbean, reaching Brazil and Paraguay in South America; hence, the iguanine recovered in the Patagonian Palaeogene greatly exceeds the present range of distribution of the group. ...
The reproductive cycle of Galapagos giant tortoises has primarily been studied in captive individuals via noninvasive methodologies, including hormonal studies, radiographs, and ultrasound. During the annual reproductive cycle, mating peaks occur during the hot season months (December–June), followed by nesting during the cool season (June–December). Females dig flask-shaped holes in the soil typically in flat areas at lower elevations where soil suitable for digging accumulates. Females deposit 1–26 eggs and close nests with a mixture of urine, feces, and soil, which then dries into a hard cap, which seals in moisture and provides a protective layer for developing embryos. Rate of development and sex of the embryos depend on the temperature of the nest: when incubation temperatures are high (above 29.5°C) embryos become female and when temperatures are low (below 28°C) male. Eggs hatch after between 90 and 270 days of incubation. Young remain in the nest for up to 1 month until all eggs have hatched and consumed their yolk reserves. Hatchlings then dig an exit hole and emerge from the nest.
... Recently, fossils found in levels attributed to the Late Oligocene of the Sarmiento Formation (Deseadan SALMA) at the locality of Cabeza Blanca, in Chubut Province [Fig. 6.3 (3)], partially fill this interval (Albino and Brizuela 2014b). The squamates recovered in this Patagonian site include two remains which belong to lizards: a tooth-bearing fragment appertaining to a maxilla or dentary (MPEF PV 1460) and an isolated presacral vertebra (MPEF PV 1463). ...
... The squamates recovered in this Patagonian site include two remains which belong to lizards: a tooth-bearing fragment appertaining to a maxilla or dentary (MPEF PV 1460) and an isolated presacral vertebra (MPEF PV 1463). The first was assigned to an indeterminate Iguanidae, whereas the latter probably belongs to an Iguaninae (Albino and Brizuela 2014b). Until the moment, no other Palaeogene iguanian was reported for South America. ...
... For the Late Palaeogene, the presence of an Iguaninae at a latitude of 45° S in the late Oligocene of Patagonia (Albino and Brizuela 2014b) is unexpected because these lizards are presently absent from the Argentine territory. Extant Iguaninae are mainly distributed from United States through Central America and the Caribbean, reaching Brazil and Paraguay in South America; hence, the iguanine recovered in the Patagonian Palaeogene greatly exceeds the present range of distribution of the group. ...
Understanding how human beings perceive and interact with the local herpetofauna is fundamental for its conservation. In this chapter, we propose looking forward to the local ecological knowledge (LEK) of the Patagonian lizards, especially the “matuasto”. The preliminary analysis of ethnohistorical sources points out the relevant role of “matuastos” in the cosmologies of the original people from Patagonia, often considered as immortal, selfish and harmful beings. Field reports agree on the warning not to disturb these territorial lizards; otherwise, they would react aggressively with bites. The recorded stories account for frequent biting events on sheep. The local perception on “matuastos” as harmful beings would provoke an attitude of caution and rejection towards them. This work provides a first overview on the relationship of lizards and the people from Patagonia while constituting an initial step for future research.
... Most of the Paleogene squamates of Argentina are known from a number of snake vertebrae mainly distributed in Patagonian localities (Simpson, 1933(Simpson, , 1935Hoffstetter, 1959;Albino, 1987Albino, , 1993Albino, , 1996Albino, , 2011aAlbino, , 2012Albino and Brizuela, 2014a). Together with other South American records, they provide useful information about the early distribution of extinct and extant taxa in Gondwana (Albino, 2011a;Albino and Brizuela, 2014b). ...
... At least four snake genera are present in Paleogene Patagonian localities: Madtsoia, Chubutophis, Waincophis and probably Boa. The Gondwanan Madtsoia is present in various Eocene to late Oligocene deposits mostly represented by vertebrae referable to the species M. bai (Simpson, 1933(Simpson, , 1935Hoffstetter, 1959;Albino, 1993Albino, , 2011aAlbino and Brizuela, 2014a). A second taxon is the boine Chubutophis grandis restricted to the middle-late Eocene (Albino, 1993). ...
... These deposits are especially rich in snake diversity, including both madtsoiids and boids, among others (Simpson, 1933(Simpson, , 1935Hoffstetter, 1959;Albino, 1987Albino, , 1990Albino, , 1996Albino, , 2011aAlbino, , 2012Rage, 1998Rage, , 2001Rage, , 2008. Recently, a sample of squamates from the Oligocene of Patagonia provided lizards (an indeterminate Iguanidae and a probable Iguaninae) and madtsoiid snakes (Albino and Brizuela, 2014a). A similar pattern is observed in Patagonian Mesozoic deposits, where snakes are represented by more than six genera whereas continental lizards include only two taxa (Albino, 2011a). ...
... No se ha reconocido hasta el momento ningún lagarto para este lapso. Tanto los cocodrilos como las serpientes del Casamayorense habrían sido los depredadores por excelencia de la abundante y diversa fauna de mamíferos herbívoros que existía entonces; en particular, dicho papel lo habrían cumplido los sebécidos, los madtsoideos y el boideo Chubutophis, los que alcanzaron tamaños excepcionalmente grandes (Albino y Brizuela 2014). ...
... Hasta hace poco tiempo el registro de Sebecidae del Deseadense representaba el más reciente crocodiliforme de Argentina; sin embargo, Lio et al. (2017) reconocieron un espécimen del grupo en el Colhuehuapense de la provincia de Río Negro, lo que indica que las condiciones climático-ambientales en esa latitud (menor que la del Chubut) eran aún de tipo subtropical-templado durante el Mioceno temprano, como lo sugieren también los escamados (Albino y Brizuela 2014 Simpson (1942), de la Fuente (1994) y de la Fuente y Vucetich (1998) reportan la presencia de una especie de Testudinidae extinto (Chelonoidis gringorum, Testudines). Entre los escamados, Brizuela y Albino (2004) describen un lagarto Teiidae (Tupinambis s.l., Scincomorpha), mientras que Albino (2008) describe restos asignables a lagartos Liolaemidae (Liolaemus sp., Iguania) y Leiosauridae (Pristidactylus sp., Iguania), Albino (1996a) describe dos Boidae (Waincophis sp. ...
The territory of the Chubut province, Argentina, is one of the richest regions in vertebrate fossils from the Lower and Middle Cenozoic of South America. In many of its classic localities there are several successive fossil levels superimposed and associated with sediments of volcanic origin that allow a precise chronological control. During this (essentially Paleogene) time period, at least two important events occur in the history of vertebrates as part of a worldwide phenomena: (1) an initial radiation and diversity that coincides with the Early Eocene Climate Optimum; (2) a turnover, or at least substantive modifications in the diversity and frequency of many clades, which occurs since the late Eocene and is defined towards the Eocene-Oligocene limit, a coincidentally with the abrupt global cooling event known as "OI-1". Since the beginning of the Miocene, the successive vertebrate faunas (especially continental mammals) express a modern character and, in many cases, a dramatic contrast with those of the Paleogene. For the Eocene-early Miocene period we cite the 513 species of continental vertebrates recognized for Chubut, which are distributed in the following faunal associations: Riochican, "Sapoan", Vacan, Barrancan, Casamayoran, Mustersan, Tinguirirican, Pre-Deseadan, Deseadan, Colhuehuapian, and "Pinturan." We synthesize the most relevant facts associated with the vertebrate fauna of this period of time, in an environmental and evolutionary climatic context. The more than 500 species of vertebrates that are recognized today from different faunas and localities within the Eocene-early Miocene sediments in the province of Chubut, clearly testify to the richness and relevance of these deposits.
... This vertebra shows a characteristic teiid form: depressed, centrum flat and triangular in ventral view, presence of a well-defined zygosphene, presence of a deep depression between the zygosphenal articular facet and the prezygapophysis (Hoffstetter and Gasc 1969;Albino and Brizuela 2014), and taken together, these characters strongly suggest teiid relationships. The trunk Palaeobio Palaeoenv vertebrae of the varanid genus Saniwa, present in the European Eocene, share some features with the vertebra from Perrière, in particular a depressed centrum and the presence of a zygosphene. ...
... without marked borders) are indicative of tupinambine affinities. Variation exists in the depth of the zygosphene among teiids: while in the teiine it is shallow, it is deep in (adult) tupinambine (Albino and Brizuela 2014). The zygosphene in PRR 2006 appears to have an intermediate depth. ...
Several teiid specimens (frontal, vertebra, maxillae) are described from the late Eocene of Europe (MP17, Phosphorites du Quercy). The results of phylogenetic analyses confirm that these European Eocene fossils belong to teiid lizards and more specifically to the subfamily Tupinambinae. So far, the Paleogene record of teiids is limited to South America and no occurrence of crown teiids is known in Europe. This disjunct distribution of teiids during the Eocene suggests transatlantic dispersal and this possibility is discussed. The presence of teiids in the European fossil record is brief (limited to standard level MP17). The circumstances that prevented the persistence of an invading clade in Europe are examined. Ecological (e.g. biotic interactions) and/or demographic (Allee effect) processes may have been involved.
... Escala= 5 mm.conocida vulgarmente como jote real, que fue reportada para el Pleistoceno del norte de Mar del Plata y constituye el primer registro paleontológico del género en la Argentina(Noriega y Areta, 2005).El desarrollo de la paleoherpetología en el sudeste de la provincia de Buenos Aires fue sostenido, especialmente desde finales de los 90 hasta la actualidad, a partir de la conformación del grupo de trabajo de la UNMdP. La contribución del grupo permitió obtener un panorama completo de la evolución de los reptiles escamosos en América del Sur desde el Cretácico hasta la actualidad(Albino y Brizuela, 2014). Más recientemente, las nuevas colecciones realizadas por el MMP aportaron materiales muy relevantes para analizar la evolución de distintos grupos de anfibios y reptiles, especialmente aves, erigiéndose en una institución con un importante reservorio paleoherpetológico de la provincia de Buenos Aires.Además del MMP, algunas pequeñas localidades del norte, sur y sudeste de la provincia constituyeron pequeños museos municipales que se están desarrollando como importantes depósitos de la historia paleontológica de la región y que son de continua consulta, incluso por parte de los paleoherpetólogos. ...
... From the fossil record, the whole group disappeared in the mid-Paleogene across most Gondwanan continents (except for Australia, see below). However, the find from Cabeza Blanca, tentatively assigned to Madtsoia, shows the persistence of these snakes through the Oligocene, at least in South America (Albino and Brizuela, 2014). One exception is Australia. ...
We here report on the first madtsoiid snake from the late Oligocene of India (the molasse deposits of Ladakh Himalaya). Madtsoiidae is an extinct group of medium sized to gigantic snakes, members of which were mostly distributed across Gondwana.
... Whether the timing of colubroid dominance was globally synchronous is unclear; a similar pattern may occur in Australia, although the Oligocene record is somewhat sparse (Scanlon et al., 2003). In South America, there is a gap in the fossil record spanning the middle Eocene to the Miocene (Albino and Brizuela, 2014). In Africa, fossils from the late Oligocene of Tanzania revealed one of the oldest colubroid dominated faunas worldwide, suggesting an earlier arrival of colubroid snakes there (McCartney et al., 2014). ...
Extant snake faunas have their origins in the mid-Cenozoic, when colubroids replaced booid-grade snakes as the dominant species. Based on fossils from North America and Europe, the timing of this faunal changeover is thought to have occurred in the early Neogene, after a period of global cooling opened environments suitable for more active predators. However, new fossils from the late Oligocene of Tanzania have revealed an early colubroid-dominated fauna in Africa suggesting a different pattern of faunal turnover there. Additionally, molecular divergence times suggest colubroid diversification began sometime in the Paleogene, although the exact timing and driving forces behind the diversification are not clear. Here we present the first fossil snake referred to the African clade Lamprophiinae, and the oldest fossil known of Lamprophiidae. As such, this specimen provides the only potential fossil calibration point for the African snake radiation represented by Lamprophiidae, and is the oldest snake referred to Elapoidea. A molecular clock analysis using this and other previously reported fossils as calibration points reveals colubroid diversification minimally occurred in the earliest Paleogene, although a Cretaceous origin cannot be excluded. The elapoid and colubrid lineages diverged during the period of global warming near the Paleocene-Eocene boundary, with both clades diversifying beginning in the early Eocene (proximate to the Early Eocene Climate Optimum) and continuing into the cooler Miocene. The majority of subclades diverge well before the appearance of colubroid dominance in the fossil record. These results suggest an earlier diversification of colubroids than generally previously thought, with hypothesized origins of these clades in Asia and Africa where the fossil record is relatively poorly known. Further work in these regions may provide new insights into the timing of, and environmental influences contributing to the rise of colubroid snakes.
... Pleurodonta (sensu Frost et al. 2001a), i.e., non-acrodontan members of Iguania, is the most diverse and widely distributed group of extant lizards in South America (Zug 1993;Uetz et al. 2019), although its fossil record in this territory is scarce Brizuela 2014a, 2015). The earliest South American Cenozoic pleurodonts are reported from the Palaeogene of Argentina, Bolivia and Brazil (Muizon et al. 1983;Estes 1983;Rage 1991;Carvalho 2001;Albino and Brizuela 2014b), but they become more abundant and diverse during the Miocene of Argentina and Colombia (Ameghino 1899;Estes 1961Estes , 1983Albino 2008;Fernicola and Albino 2012;Albino et al. 2017). So far, only one pleurodont has been formally described for the Pliocene of Argentina; this is Uquiasaurus heptanodonta, which has been postulated as an extinct species basal to the clade Liolaemidae (Leiocephalidae + Tropiduridae) (Daza et al. 2012). ...
The Pliocene record of iguanian pleurodont lizards of South America is scarce, although it is plentiful during the Miocene, including extant genera. Here we describe a partial dentary from the Pliocene Saldungaray Formation of the southwestern Buenos Aires province, Argentina. It is assigned to the extant tropidurid Stenocercus. This is the first fossil attributed to this genus and together with Uquiasaurus from northern Argentina are the only pleurodont iguanians from this age.
... Además, la confirmación de la presencia de una forma extinta de Teiidae Tupinambinae, Lumbrerasaurus scagliai, en el Eoceno temprano de Argentina (Donadío, 1985;Brizuela y Albino, 2015), indica que esta familia ya entonces se encontraba diversificada en sus dos subfamilias, concordando con un posible origen en el Cretácico-Paleoceno, como lo proponen datos moleculares (Giugliano et al., 2007). Con respecto al Oligoceno, recientemente se reconoció un Iguanidae y especialmente un posible Iguaninae, el cual sugiere que el grupo tenía una distribución más extensa que la actual, alcanzando el norte de la Patagonia (Albino y Brizuela, 2014b). ...
The squamates are a successful group of reptiles which includes more than 9,600 extant species. Their evolution in South America, scarcely illustrated by the incomplete and episodic fossil record, is a consequence of the complex geological and paleoclimatic history of this part of the world. The Mesozoic squamate record is concentrated in Argentina and Brazil, with less presence in Bolivia. Both major squamate clades (Iguania and Scleroglossa) are present during the Cretaceous, where snakes were common and diverse, involving some of the most primitive terrestrial forms. Paleogene and Neogene squamates were mainly recorded in Argentina, Bolivia, Brazil, Colombia, Peru, and Venezuela. Lizards were
uncommon in Paleogene deposits but snakes showed an important diversity which included at least two extant boid snakes (Boaand Corallus) and extinct forms. The Miocene is especially relevant because of the first recognition of some extant genera of Iguanidae (Liolaemus, Pristidactylus), Teiidae (Tupinambis), and other Boidae (Eunectes, probably Epicrates), although extinct genera were also present. First occurrence of Colubridae is from the early Miocene, whereas Scolecophidia appeared in the middle Miocene, and Viperidae in the late Miocene. The earliest Amphisbaenia of South America is recorded in the Pliocene, and the earliest Gekkonidae, Anguidae and Elapidae come from the Pleistocene. Most Pleistocene and Holocene squamate remains correspond to living genera, including some extant species.
... The shared characters are: procoelia, large size, well-developed zygosphene -zygantrum system with a developed tenon and notched anterior zygosphenal border, no prezygapophysial process, triangular vertebral centrum (in outline), dorsoventrally compressed cotyle and condyle, and marked precondylar constriction. Among Teiidae, several differences have been observed at subfamiliar level (Donadío 1985;Brizuela 2010;Albino and Brizuela 2014). In Tupinambinae there is a low, wide and vague ventral sagittal crest unlike the well-defined sagittal crest observed in Teiinae. ...
The Lumbrera Formation in north-western Argentina is notable for preserving lizard remains from the Palaeogene of South America. In this paper, we offer a re-description and re-evaluation of the material belonging to the holotype of the teiid lizard Lumbrerasaurus scagliai (Donadío, 1985) recovered from sediments of the Lumbrera Formation near Pampa Grande, Salta province, Argentina. Lumbrerasaurus scagliai is considered here as an extinct genus of Tupinambinae. These remains are the earliest record of teiid lizards and confirm the presence of tupinambine teiids in the South American Palaeogene.
Saniwa is an extinct genus of varanid squamate from the Eocene of North America and Europe. Up to now, only one poorly known species, Saniwa orsmaelensis Dollo, 1923, has been reported from Europe. Diagnostic material was limited to vertebrae with only preliminary description and no figure provided, except of one dorsal vertebra that was designated as the lectotype. New specimens from the earliest Eocene of Dormaal, Belgium and Le Quesnoy, France, including recently recovered skull material, are described and illustrated here. These fossils representing the oldest varanid squamate allow further comparisons with the type species, Saniwa ensidens Leidy, 1870, from the early and middle Eocene of North America and to propose a new diagnosis for S. orsmaelensis. Its arrival in Europe is probably linked to rapid environmental changes around the Paleocene Eocene Thermal Maximum (PETM). The occurrence of S. orsmaelensis is restricted to the early Eocene of northwest Europe and paleogeographic considerations regarding the distribution of the genus Saniwa Leidy, 1870 suggest an Asian origin, but an African origin cannot be completely excluded.
The squamates constitute a significant part of the present-day South American herpetofauna, and their fossils provide crucial evidence for understanding the origin and evolution of the main clades. The fossil record of squamates in Patagonia is still scarce but it represents one of the most prolific of all of South America. An updated systematic review of the available information of Patagonian fossil lizards is summarized in this chapter. The oldest lizards of Patagonia are found as far back as the Upper Cretaceous and include materials referred to two of the most diverse extant clades: Iguania and Scincomorpha. Palaeocene and Eocene interestingly do not provide any lizard specimens from this time frame, but the record reappears in the Late Oligocene with iguanians. A significant increase in materials is revealed later in the Neogene. Early Miocene lizards include the first appearance of extant genera (the iguanids Liolaemus and Pristidactylus and the teiids Tupinambis and Callopistes). Late Early Miocene deposits provide materials of Pristidactylus and Tupinambis, whereas an indeterminate tupinambine of the Mid-Miocene is the youngest Neogene record of a lizard in Patagonia. Palaeoclimatic changes affected the distributional patterns of lizards in Patagonia, restricting the distribution of Pristidactylus and Tupinambis, which, during the Miocene, extended to localities more southern than at present. The uplift of the austral Andean cordillera would have been decisive for the diversification of Liolaemus and Pristidactylus on both sides the Andes, whereas the trans-Andean teiid Callopistes had a widespread distribution in the past, reaching the Pampean Region and Patagonia, in Argentina.
Fossil vertebrae from the early Miocene of France (Loire Basin) are described. They show several characters generally regarded as varanid synapomorphies. A phylogenetic analysis of these vertebrae is performed with a subset of morphological data taken from several large morphological data sets (vertebral characters) and it confirms an attribution to varanid lizards. Moreover, referral of isolated vertebrae from the Eocene–Oligocene of Egypt to varanids is confirmed. The use of subsets of large morphological data sets in phylogenetic analysis of fossils (especially incomplete remains) is discussed and advocated for, and we argue that convergence between tree topologies obtained from different kinds of data sets is a key issue in inferring the phylogenetic position of fossil taxa.
Citation for this article: Augé, M. L., and B. Guével. 2018. New varanid remains from the Miocene (MN4–MN5) of France: inferring fossil lizard phylogeny from subsets of large morphological data sets. Journal of Vertebrate Paleontology. DOI:10.1080/02724634.2017.1410483.
Madtsoiids are among the most basal snakes, with a fossil record dating back to the Upper Cretaceous (Cenomanian). Most representatives went extinct by the end of the Eocene, but some survived in Australia until the Late Cenozoic. Yurlunggur and Wonambi are two of these late forms, and also the best-known madtsoiids to date. A better understanding of the anatomy and palaeoecology of these taxa may shed light on the evolution and extinction of this poorly known group of snakes and on early snake evolution in general. A digital endocast of the inner ear of Yurlunggur was compared to those of 81 species of snakes and lizards with known ecological preferences using three-dimensional geometric morphometrics. The inner ear of Yurlunggur most closely resembles both that of certain semiaquatic snakes and that of some semifossorial snakes. Other cranial and postcranial features of this snake support the semifossorial interpretation. While the digital endocast of the inner ear of Wonambi is too incomplete to be included in a geometric morphometrics study, its preserved morphology is very different from that of Yurlunggur and suggests a more generalist ecology. Osteology, palaeoclimatic data and the palaeobiogeographic distribution of these two snakes are all consistent with these inferred ecological differences.
Cenozoic South American land mammals demonstrated to be the richest and most eloquent known testimonies to infer the geobiotic evolution of the continent throughout the geological span. The concept and practice followed to recognize by them the South American Land Mammal Ages (SALMAs) are explained. Likewise, it is explained the analytical method used to recognize four hierarchical ranks of organization of the 16 SALMAs, which are distinguished as “faunal cycles” (from higher to lower, Megacycles, Supercycles, Cycles and Subcycles). Each of these cycles is defined by an unique association of mammal families, and on the whole are apparently correlated to a hierarchy of world-wide and regional changes in environmental conditions. The Faunistic Cycles are used as “standard units” because they appear to be more closely related to physical and biological regional phenomena. The long-standing autochthonism showed by the South American Late Cretaceous-Cenozoic mammals, as well as the peculiar South American biogeographical history, is briefly analyzed as associated to the climatic shifts related to eustatic falls and geodynamic processes. The successive Late Cretaceous-Cenozoic range pattern and facies of land mammal-bearing deposits is also analyzed in association to eustatic falls and geodynamic processes. Finally, using this background, and as base for the seven Faunistic Cycles so far recognized, the general pattern of evolution of land mammals is chronologically and synthetically analyzed, and particularly, the trends and features of each of the Faunistic Cycles.
Key Words: Land mammals, Cenozoic, South America. geobiotic evolution.
O objetivo deste trabalho é apresentar uma nova espécie de Madtsoiidae (Reptilia, Serpentes) procedente da Formação dos Alamitos (Campaniano – Maastrichtiano Inferior) na Província de Rio Negro, Argentina. Alamitophis elongatus sp. nov. se diferencia de outra espécie conhecida deste gênero, A. argentinus Albino nos seguintes aspectos: (1) centro vertebral mais alongado; (2) zigosfeno com um tubérculo anterior mediano e (3) sinapófises mais distantes do centro vertebral. A presença de madtesoideos no Cretáceo Superior da Argentina favorece a hipótese sobre a diferenciação dos abtinofidios gonduânicos e sobre a existência de clima subtropical no norte da Patagonia no Cretáceo Superior. A identificação desta nova espécie de matsoideo evidencia uma diversidade específica desta família, no Cretáceo sul-americano, maior do que se supunha até então.
Vertebral remains assignable to the extant snake Boa constrictor, found in the Toropí Formation (Late Pleistocene, Lujanian age) at Arroyo Toropí, northeastern Argentina, are here described. These remains represent the first snake record from the Lujanian age and determine the minimum age for the species as 50–35 ka BP. Boa is presently absent in northeastern Argentina. Interruption of the continuity between the Mesopotamian and Brazilian faunas, including disappearance of Boa from Mesopotamia (northeastern Argentina), occurred subsequent to the Late Pleistocene and might be explained by changes in the Paraná and Uruguay Rivers. In addition, previous taxonomic referral of fossils to ?Boa is revised, with the conclusion that the specimen from the Early Eocene is tentatively referred to this genus, whereas that from the Pliocene is an indeterminate Boinae.
A new species of Pristidactylus from the southern Patagonian region of Argentina is described. This new species shows peculiar throat coloration in males, a secondary sex character that is unique in this genus. Different character combinations led to the revalidation of Pristidactylus araucanus from the basaltic districts of Mendoza and Neuquén, Argentina. The conservative retention of the juvenile pattern in adult females, besides other mensural characters in both sexes, indicates its specific identity relative to Pristidactylus scapulatus and Pristidactylus fasciatus. General considerations of the evolutionary history of the genus Pristidactylus are reviewed and a key to the Argentinean taxa is provided.
A new Early Miocene iguanian lizard from New Mexico is described. This specimen is the oldest demonstrable member of the iguanine clade as determined by its possession ofderived characters of Iguaninae as a whole and those of its two primary subclades. The phylogenetic relationships among iguanines are reevaluated with the inclusion of this and another recently described fossil iguanine. The fossil taxa increase the amount of phylogenetic resolution, and a single most parsimonious tree is found. The new fossil appears to be the sister group of Dipsosaurus and the clade formed by both taxa is the sister group of the remaining iguanines. Monophyly of the new taxon is poorly supported.
Two small early Miocene madtsoiid snakes from Riversleigh, NW Queensland are described as Nanowana godthelpi gen. et sp. nov. and N. schrenki gen. et sp. nov. Jaw elements of the
former are depressed, lack ankylosed teeth, and have alveoli of nearly uniform size; these
features are interpreted as signs of a coadapted character complex ('arthrodonty') where the
teeth are attached to the jaws by a fibrous hinge. This condition is associated with a diet of
hard-scaled scincid lizards. The latter species retains ankylosis, and has strongly enlarged
teeth on the anterior dentary and middle maxilla indicating a distinct method of subduing
prey, but extant analogues are also predominantly scincivorous. Departure in each species
from the nearly homodont, ankylosed condition in other madtsoiids is interpreted as adaptation
to a diet of scincid lizards. These divergent, but functionally parallel specialisations are
likely to be independently derived from the ancestral condition.
Small madtsoiid snakes referred to Patagoniophis and Alamitophis are represented by specimens of all major regions of the vertebral column from the Tingamarra Local Fauna (Early Eocene; Murgon, Queensland, Australia), and are diagnosed as distinct from members of the same genera from the Late Cretaceous (Campanian -?Maastrichtian) of Patagonia, Argentina. The Tingamarra deposit has also produced ribs and dentary bones of two distinct morphotypes, which are provisionally assigned to the same two taxa. A single rib fragment represents a larger form comparable to South American Madtsoia spp., although not positively identifiable as a madtsoiid. It is inferred that two (and probably three) madtsoiid lineages had Antarctic-spanning distributions during the Late Cretaceous and/or Paleocene, with implications for their biology and that of their Neogene and Quaternary descendants.
Los lagartos que en Argentina se conocen como "iguana roja" o "caraguay" pertenecen al género Tupinambis, uno de los saurios de mayor talla del continente; tienen importancia económica, tanto por su cuero como por su carne. Se reconocen seis especies actuales, que se distribuyen en América del Sur desde Colombia hasta el norte de la Patagonia, Argentina (Cei, 1993). Por su amplia distribución y abundancia son utilizados como animales de laboratorio por lo que es importante el conocimiento detallado de su anatomía. Es por ello que aquí presentamos en un Atlas fotográfico la morfología externa y osteología de Tupinambis rufescens.
ATENCION: en "Linked data" se puede descargar el archivo "Atlas de Tupinambis rufescens - Presentación PowerPoint.rar" que contiene el Atlas fotográfico como una presentación PowerPoint; comenzar a ver la presentación ejecutando primero el archivo "Indice.pps" que contiene los enlaces hacia los demás archivos.
BioOne (www.bioone.org) is a nonprofit, online aggregation of core research in the biological, ecological, and environmental sciences. BioOne provides a sustainable online platform for over 170 journals and books published by nonprofit societies, associations, museums, institutions, and presses. ABSTRACT.—A fragmentary fossil lizard from Uquía Formation (Late Pliocene), Jujuy Province, Argentina, is described. The material consists of disarticulated cranial bones from the snout and jaw that were part of a microvertebrate fossil assemblage generated by accumulation of predatory birds pellets. The phylogenetic analysis of 396 morphological characters indicates a sister-group relationship between the new taxon and a clade formed by the families Liolaemidae, Leiocephalidae, and Tropiduridae. Its uncertain position and substantial morphological differences justify its placement in a new genus. We present a detailed osteological description of the material, and compare the morphological features with other Iguanoidea. In the context of this new analysis of Iguania, we included Pristiguana brasiliensis, the oldest know iguanian from South America. The results of this analysis support the monophyletic status of Iguanoidea and other groups within Iguania that are named and diagnosed.
Madtsoiidae are a group of archaic snakes, widely distributed in the Upper Cretaceous of Gondwanan landmasses (South America, Madagascar, India, Africa), but otherwise reported outside Gondwana based only on scarce material from a few southern European localities. Here, we describe associated snake remains from uppermost Cretaceous (Maastrichtian) beds of the Haţeg Basin, Romania, as a new small-madtsoiid taxon, Nidophis insularis, gen. et sp. nov. Nidophis, represented by a large number of well-preserved vertebrae and ribs that apparently belonged to one individual, is one of the best-known Cretaceous madtsoiids, and the most completely documented member of the family from Europe. Phylogenetic analyses place the new taxon within a moderately supported Madtsoiidae, closely related to Herensugea from the Upper Cretaceous of Spain. The two European taxa, together with other small madtsoiids, are recovered as the sister taxon to a second madtsoiid clade including large-to-gigantic forms such as Madtsoia, Wonambi, and Yurlunggur. The presence of these small madtsoiids, together with that of Menarana, in the uppermost Cretaceous of Europe, suggests that early widespread distribution of madtsoiids, extending over the southern part of Europe, instead of late northward immigration from Gondwanan landmasses, as proposed previously, might account for the paleobiogeographic distribution of Cretaceous Madstoiidae.
SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP
French zoologist and naturalist Georges Cuvier (1769–1832), one of the most eminent scientific figures of the early nineteenth century, is best known for laying the foundations of comparative anatomy and palaeontology. He spent his lifetime studying the anatomy of animals, and broke new ground by comparing living and fossil specimens - many he uncovered himself. However, Cuvier always opposed evolutionary theories and was during his day the foremost proponent of catastrophism, a doctrine contending that geological changes were caused by sudden cataclysms. He received universal acclaim when he published his monumental Le règne animal, which made significant advances over the Linnaean taxonomic system of classification and arranged animals into four large groups. The sixteen-volume English translation and expansion, The Animal Kingdom (1827–35), is also reissued in the Cambridge Library Collection. First published in 1817, Volume 1 of the original version covers mammals and birds.
Describes a new marine snake, Pterosphenus sheppardi from upper Eocene localities of Ecuador. This species is less specialized than contemporaneous northern forms (known only from Alabama and north Africa). It is concluded that Pterosphenus cannot have derived from specialized forms of Palaeophis, such as P. typhaeus, but from an earlier form such as P. toliapicus. Differentiation into species was divergent rather than linear.
Eighteen large snake vertebrae from a single locality within the Camfield Beds (middle Miocene) at Bullock Creek, Northern Territory, Australia, represent a single individual of Yurlunggur camfieldensis new genus and species. The family Madtsoiidae is correctly referred to the Alethinophidia, but distinguished from all other Alethinophidian taxa by combinations of vertebral and cranial characters most fully represented in Wonambi naracoortensis.
Coastal exposures of the Santa Cruz Formation in southern Patagonia have been a fertile ground for recovery of Early Miocene vertebrates for more than 100 years. This volume presents a comprehensive compilation of important mammalian groups which continue to thrive today. It includes the most recent fossil finds as well as important new interpretations based on 10 years of fieldwork by the authors. A key focus is placed on the paleoclimate and paleoenvironment during the time of deposition in the Middle Miocene Climatic Optimum (MMCO) between 20 and 15 million years ago. The authors present the first reconstruction of what climatic conditions were like and present important new evidence of the geochronological age, habits and community structures of fossil bird and mammal species. Academic researchers and graduate students in paleontology, paleobiology, paleoecology, stratigraphy, climatology and geochronology will find this a valuable source of information about this fascinating geological formation.
A large collection of lizard vertebrae from northern Africa represents the oldest unambiguous occurrence of the genus Varanus. The fossils come from late Eocene and early Oligocene freshwater deposits of the Fayum, Egypt, an area noted for many significant primate finds. The recovery and identification of this material indicate that the genus Varanus arose in Africa, before dispersing to Australia and Asia. This dispersal occurred prior to the early to mid-Miocene, by which time fossil Varanus are known from Australia and Eurasia. Although the dispersal route remains unknown, the lizard material reported here supports the hypothesis that a corridor existed allowing freshwater and terrestrial organisms to cross from Africa to Asia.
The described indeterminate boid snake was collected in rocks belonging to the Sarmiento Formation and exposed at La Gran Hondonada (Chubut Province, Argentina). This is the first snake record for the mid—late Eocene Mustersan South American land-mammal age. The specimen proves that medium- to large-sized boids inhabited the Patagonian region during most of the Palaeogene, suggesting climatic conditions warmer than those established at the beginning of the Neogene.
The evolution of squamates in South America is the result of the complex geological and paleoclimatic history of this part of the world. The incomplete and episodic fossil record allows us to know only a small part of this evolution. Most Mesozoic squamate remains come from the Patagonian region, but remarkable specimens have also been recovered from Brazil. Both major squamate clades (Iguania and Scleroglossa) are present in the South American Mesozoic. Remains of Mesozoic snakes are common and diverse in Cretaceous deposits, including some of the most primitive terrestrial forms. Paleogene and Neogene squamate remains have been recognized from Argentina, Bolivia, Brazil, Colombia, Ecuador, Peru, and Venezuela. Paleogene lizard record appears to be scarce in comparison to that of the Mesozoic, whereas snakes show an important Paleogene diversity. At least two extant boid snakes appeared during this epoch (Boa and Corallus). The South American Miocene included some extant genera of Iguania, Teiidae, and Boidae but extinct genera were also present. "Colubrids" appeared at the early Miocene, whereas the first viperid is known from the late Miocene. Most of the Paleogene and early Neogene squamate families and genera have been recognized outside their current range of distribution following favorable climatic conditions for ectothermic vertebrates. During the latest Miocene and Pliocene few extant squamate taxa are found to occur outside their present distribution. The earliest amphisbaenian of South America is known from the Pliocene. Most Pleistocene and Holocene squamate remains are assigned to living genera, and some extant species were recognized. Anat Rec, 2013. © 2013 Wiley Periodicals, Inc.